Method of forming sheet-metal products.



F W. GUIBERT.

METHOD OF FORMING SHEET METAL PRODUCTS.

APPLICATION FILED ocr.2s.191e.

1,271,703. Patented July 9, 1918.

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METHOD OF FORMING SHEET-METAL PRODUCTS.

Specification of Letters Patent. I

Patented July 9, 1918.

Application filed October 28, 1916. Serial No. 128,191.

To all whom it may concern Be it known that I, F WALTER GUIBERT, a citizen of the United States of America, residing at Detroit, in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Methods of Forming Sheet-Metal Products, of which the following is a specification, reference being had therein to the accompanying drawings.

The invention relates to sheet-metal manu-- factured by cold-rolling process and particularly designed for use in the forming of articles in which the metal is drawn or stretched while fashioned. In the present state of the art cold-rolled sheet-metal is largely used in the manufacture of various articles by pressing or drawing operations, but it has been found that in the completed articles there are strain marks which are visible on the surface of the metal. These marks are not breaks in the surface or the skin of the metal but rather are caused by the unequal distribution of the core or interior of the sheet, resulting in uneven surfaces. quently polished or coated with enamel the irreglflarities in the surface become apparent and detract from the finished appearance.

Various attempts have been made to correct this defect, such as annealing the metal and subjecting the same to further rolling, but without great success. Annealing, where carried to the dead soft condition, causes strain marks in the draw, while a further hardening by cold-rolling the metal usually renders it unsuitable for subsequent fashioning. I have discovered that by the transverse flexing, bending or working of the metal the interior thereof is so altered in structure as to avoid strain marks when subsequently drawn or fashioned, while at the same time the metal remains in a soft condition suitable for refashioning.

Various specific methods may be employed Thus where the article is subsefor thus working the metal and the same may be carried out in various constructions of apparatus. I prefer, however, to employ an apparatus similar to the roller levelers which are used in straightening sheets, but modified by the arrangement of some of the rolls in different planes. Thus in a usual form of roller leveler, a series of parallel rolls are arranged in a common plane to feed the sheet in a straight line, but with my modified apparatus the sheet when passing through the rolls is laterally deflected so as to transversely Work the metal. In the drawing, I show diagrammatically such an apparatus, in which A A etc. and B B etc. are two series of rolls between which the sheet 0 is passed. The rolls A and B are laterally oflset to form a bend D in the sheet passing therebetween,.which is subsequently straightened out by rolls A A B B and if desired prior to this straightening operation the sheet may be deflected in the opposite direction by offset rolls A B I have found that cold-rolled sheet-metal which is subjected to this working operation will be free from strain marks when subsequently fashioned by a drawing or stretching process, and I attribute this new property to the altered condition of the interior of the metal which lies between the opposite skin faces. Whatever the cause may be, the result is a new property,-viz., freedom from strain marks when subsequently stretched. My new process is therefore exceedingly valuable as it dispenses with the laborious and costly grinding or refinishing of the surfaces of fashioned articles which has heretofore been necessary.

What I claim as my invention is:

The process of forming sheet-metal articles, free from strain marks, comprising the transverse bending or working of cold-rolled sheet-metal and the subsequent drawing or stretching of the same to fashion the article.

In testimony whereof I aflix my signature.

F WALTER GUIBERT. 

